Fluidized bed sterilizing process

ABSTRACT

A METHOD AND APPARATUS FOR STERILIZING POWDER IN SEALED BAGS COMPRISING PLACING FINELY DIVIDED MATERIAL, SUCH AS POWDER, SEALED IN SEMI-PERMEABLE BAGS IN CONTAINERS WITH A SIDE HAVING AN INLET AND OUTLET FOR GAS. THE BAGS HAVE PARTITIONS AND HAVE OPENINGS WHICH MAY REGISTER THE GAS INLETS AND OUTLETS. THE BAGS ARE SPECIALLY DESIGNED OF SEMI-PERMEABLE MATERIAL WHICH ALLOWS THE GAS TO FLOW THROUGH THE MATERIAL AND OUT THE OUTLET OF THE CONTAINER. THE APPARATUS FUNCTIONS AS A FLUID BED AND THE POWDER IN THE BAG BECOMES FLUIDIZED.

Aug. 17, 1971 K. KERELUK Emu. @fiOOJfl FLUIDIZED BED STERILIZING PROCESS Filed Oct. '7, $959 CID F/GJ

' INVENTORS.

MM Kma [/K Mai/9751mm CM 1 4M Arm/aver.

United States Patent O 3,600,127 FLUIDIZED BED STERILIZING PROCESS Karl Kereluk, Fairview, and Robert S. Lloyd, Erie, Pa., assignors to American Sterilizer Company, Erie, Pa. Filed Oct. 7, 1969, Ser. No. 864,312

Int. Cl. A611 1/00 US. Cl. 2158 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for sterilizing powder in sealed bags comprising placing finely divided material, such as powder, sealed in semi-permeable bags in containers with a side having an inlet and outlet for gas. The bags have partitions and have openings which may register the gas inlets and outlets. The bags are specially designed of semi-permeable material which allows the gas to flow through the material and out the outlet of the container. The apparatus functions as a fluid bed and the powder in the bag becomes fluidized.

STATEMENT OF INVENTION This invention relates to sterilizers and, more particularly, to sterilizers for powder that operate on the fluld bed principle.

REFERENCE TO PRIOR ART The apparatus and method disclosed herein constitutes an improvement over Pat. 3,341,280 which shows a sterilizing device for powder which operates on the fluid bed principle.

OBJECTS OF THE INVENTION It is an object of the invention to provide an improved sterilizing method.

Another object is to provide a process for sterilizing powder that is economical, simple and efiicient to use.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of the apparatus according to the invention.

'FIG. 2 is an isometric view of the sterilizing container with the special bag therein.

FIG. 3 is a view of another embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Now with more particular reference to the drawings, the gas manifold circulating system is shown in FIGS. 1 and 2. It shows the gas cylinder connected to a gas console 11 through a line 26. The gas may be any of the well known microbiocidal sterilizing gases, for example, ethylene oxide. This is fed into the gas console 11 which is connected to the gas manifold circulating system 12 by line 13. The gas console circulating system has a recording, controlling instruments indicated at 14 and pilot lights, gauges and switches indicated at 15. The gas manifold circulating system is connected to the sterilizing units 16 which contain pre-packed powders in disposable plastic bags. The bags may be of semi-permeable membrane, for example, polyethylene or any other of the well known semipermeab1e materials.

The sterilizing unit is shown in enlarged isometric view in FIG. 2. The outside container 16 which may be generally cylindrical in shape with the plastic bags 19 supported in it. The gas system is connected to the container 16 by lines 18 and the gas moves from the container through the bacteriological filter 20 and is thereby circulated through the container. The drum or container 16 may be of a size to hold, for example, a ten-pound bag 3,60,127 Patented Aug. 17, 1971 of the material. The bag is separated into sections by means of a partition or partitions 27 and 28 which have pores permitting the passage of gas. The bottoms 28 are supported above the bottom of the drum approximately five inches, for example, and are spaced from each other as shown. The bottom 28 has pores therein of approximately 10 to 25 m. (.0l0.025 inch in diameter) and the bottom 27 has holes 21 therein which may be, for example, 25-l00 m. (.025-.l00 inch in diameter).

The gas manifold circulating system as shown provides an enclosure which contains the following components:

(1) A gas manifold or pipe 13 connected directly to the gas charge line emerging from the gas console 11. The manifold will be located in a convenient area in the apparatus preferably in the lower half.

(2) A second manifold or pipe located in a convenient area in the upper half of the apparatus and connected to the lower manifold.

(3) A number of outlet lines 18 extending from the lower manifold for purposes of connecting to the gas inlet port on the powder bag 27-sterilizercontainer unit.

(4) A similar number of inlet lines 17 extending from the upper manifold for purposes of connecting to the gas outlet port on the powder bagsterilizercontainer unit.

(5) A gas circulation system 12 which pumps or dis tributes the gaseous mixture from the powder bag into the upper gas manifold and from there to the lower gas manifold for re-entry into the powder bag.

(6) A heating system for maintaining the temperature of the gas at F. to 130 F. as it is brought into the upper gas manifold and circulated to the lower gas manifold for re-entry into the powder bag.

(7) A bacterial retentive filtering system for purposes of filtering the gas as it returns from the powder bag to the upper manifold for recirculation.

(8) A humidification system for purposes of humidifying the circulating gas to 1030% R.H. within the gas manifold system.

(9) An analyzer for indicating, recording and controlling the humidity in the gaseous atmosphere during circuation.

(10) An analyzer for indicating, recording and controlling the ethylene oxide concentrations in the gaseous atmosphere at 500 mg./l. during circulating. The controlling mechanism of this analyzer will be integrated in the gas charging system on the gas console so that additional gas can be introduced into the circulating system to increase the ethylene oxide concentration when required.

(11) Suitable power switches, pilot lights, pressure gauges and other visual aid mechanisms as required for the optimum performance of the gas manifold-circulating system.

In the embodiment of FIG. 3, an alternate system is disclosed which comprises a single sterilizing drum 116 connected to a gas charging system 110. This embodiment is also designed according to the fluidized bed concept in which powders can be sterilized in a manner similar to that described in connection with FIGS. 1 and 2. The unit may contain a built-in circulating system for removing the gaseous atmosphere from the upper part of the unit and returning the gas to the lower part of the sterilizer. Pump P circulates gas from cylinder to the space below porous bottom 128 back through line 117 to connect with inlet line 118.

Heating and humidifying systems may be incorporated in the sterilizer for purposes of maintaining the circulating gaseous atmosphere at approximately 130 F. and 10- 30% RH, respectively.

The sterilizer may be connected to a suitable gas console containing the necessary mechanisms and/ or systems for proper gas vaporization, heating, humidifying and flow-rate to the sterilizing chambers.

The sterilizer may also be designed for containing varying sized packages of powders or suitable containers for directly exposed loose powders and which can be removed from the sterilizer under sterile conditions for aseptic packaging of the powders.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1.A method of sterilizing finely divided material comprising packaging said material in a closed plastic bag made of a semi-permeable membrane and having a porous partition therein positioned adjacent to and spaced from the bottom of the bag, the material being supported by said porous partition,

placing the bag having the packaged material in a closed container having an upper gas outlet and a lower gas inlet such that a portion of the bag containing the porous partition is between the gas outlet and inlet of the container and the porous partition is spaced from the container bottom,

circulating a microbiocidal gas in through said inlet,

up through said porous partition and finely divided material and out through said outlet for a predeter-' mined sterilizing period, the velocity and flow characteristics of the circulating microbiocidal gas being such as to fluidize the finely divided material within the bag during the sterilizing period, and removing the bag having the packaged material from the container after the sterilizing period.

2. A method of sterilizing finely divided material comprising packaging said material in a closed plastic bag having a porous partition therein positioned adjacent to and spaced from the bottom of the bag, the material being supported by said porous partition, said bag further having an upper gas outlet and a lower gas inlet in a side thereof with the lower gas inlet being disposed at a level between the porous partition and the bottom of the bag,

placing the bag having the packaged material in a closed container having an upper gas outlet and a lower gas inlet such that the gas outlet and inlet of the bag are in registry with the gas outlet and inlet of the con tainer and the porous partition is spaced from the container bottom,

circulating a microbiocidal gas in through said inlets, up

through said porous partition and finely divided material and out through said outlets for a predetermined sterilizing period, the velocity and flow characteristics of the circulating microbiocidal gas being such as to fiuidize the finely divided material within the bag during the sterilizing period, and

removing the bag having the packaged material from the container after the sterilizing period.

References Cited UNITED STATES PATENTS 2,018,992 10/1935 'Bohmer 2158X 2,529,710 11/1950 Singh 99153 3,341,280 9/1967 Eolkin 2l-58 3,341,335 9/1967 Eolkin ct al. 21-58X 3,477,807 ll/l969 Ernst 21-58 3,498,742 3/1970 Long 2191 MORRIS O. WOLK, Primary Examiner I. T. ZATARGA, Assistant Examiner US. Cl. X.R.

219l; 992ll, 214 

